Altered gut microbiota in patients with small intestinal bacterial overgrowth

• Published in: Journal of gastroenterology and hepatology Vol. 38; no. 1; pp. 61 - 69
• Main Authors: Bamba, Shigeki, Imai, Takayuki, Sasaki, Masaya, Ohno, Masashi, Yoshida, Shinya, Nishida, Atsushi, Takahashi, Kenichiro, Inatomi, Osamu, Andoh, Akira
• Format: Journal Article
• Language: English
• Published: Australia Wiley Subscription Services, Inc 01.01.2023
• Subjects: Bacteria; Breath Tests; clinical intestinal disorders; Duodenum - microbiology; Dysbacteriosis; Gastrointestinal Microbiome - physiology; Gut microbiota; Humans; Hydrogen; intestinal disorders; Intestinal microflora; Intestine, Small - microbiology; Microbiomes; Microbiota; Relative abundance; RNA, Ribosomal, 16S - genetics; rRNA 16S; small bowel; Small intestine; clinical intestinal disorders; intestinal disorders; small bowel
• ISSN: 0815-9319; 1440-1746; 1440-1746
• DOI: 10.1111/jgh.16013

Background and Aim Small intestinal bacterial overgrowth (SIBO) is diagnosed by using quantitative culture of duodenal aspirates and/or a hydrogen breath test. However, few studies have analyzed bacterial microbiota in Japanese patients with SIBO. Methods Twenty‐four patients with any abdominal symptoms and suspected SIBO were enrolled. Quantitative culture of duodenal aspirates and a glucose hydrogen breath test were performed on the same day. SIBO was diagnosed based on a bacterial count ≥ 103 CFU/mL or a rise in the hydrogen breath level of ≥ 20 ppm. The composition of the duodenal microbiota was analyzed by 16S rRNA gene sequencing. Results Small intestinal bacterial overgrowth was diagnosed in 17 of the 24 patients (71%). The positive rates for the hydrogen breath test and quantitative culture of duodenal aspirates were 50% and 62%, respectively. Patients with SIBO showed significantly reduced α‐diversity compared with non‐SIBO patients, and analysis of β‐diversity revealed significantly different distributions between SIBO and non‐SIBO patients. In addition, the intestinal microbiome in SIBO patients was characterized by increased relative abundance of Streptococcus and decreased relative abundance of Bacteroides compared with non‐SIBO patients. Conclusions Duodenal dysbiosis was identified in patients with SIBO and may play a role in the pathophysiology of SIBO.